Electric calling apparatus for telephones.



0. ADAMS-RANDALL. I ELECTRIC CALLING APPARATUS FOR TELEPHONES.

APPLIUATION FILED DBO. 22, 1903.

2 SHEETS-SHEET l.

f [72 e en/02': @OLZ: W

PATENTED JAN. 15, 1907.

PATENTED JAN.15, 1907. G. ADAM$-RANDALL ELECTRIC UALLING APPARATUS FOR TELEPHONES.

APPLICATION FILED DEC. 22 1003.

2 SHEETSAHEET 2 UNITED STATES PATENT OFFIG.

CHARLES ADAMS-RANDALL, OF NEW YORK, N. Y.

ELECTRIC CALLlNG APPARATUS FOR TELEPHONES.

Specification of Letters Patent.

Patented Jan. 15, 1907.

Application filed December 22, 1903. Serial No: 186.254.

. T at whom it may concern.-

ted by like signs.

Be it known that 1, CHARLES ADAMS-RAN-- DALL, a citizen of the United States, residing in the borough of Manhattan, city of New York, county of New York, and State of New. York, have invented certain new and useful Improvements in Electric Calling Apparatus for Telephones, of which the following is a specification.

This invention relates to an electric calling apparatus for telephones; and its object is to improve the efllciency and adapt the apparatus for use with a telephone system upon a telegraph-line or composite telephony and telegraphy whereby telephone calls-can be givnwithout interference with the telegraphic instruments in ordinary use thereon.

in the accompanying drawings, Figure 1 is a diagrammatic view of one form. of apparatus embodying my improvements and showing the parts employed at each station. Fig. 2 is a diagram showing particularly one we of connectin the primary and secon ary coils of a p urality of induction-coils in the. usual way, which-forms one member oi an interrupter, the other member thereof consisting of the adjustable stop or contact 8, which 18 in the form of a screw tapped into a post 9, insulated from the base 10. Said local circuit is normally open, but readily closed by depressing the ush-button or other circuit-closer, which 0 oses the circuit through the clectromagnet, said circuit be ing autmmitically made and broken by the fiction, of the vibrator so long as the circuit is closed at the push-button.

A second local circuit (designated as 11) includes a source of power 12, a primary 13 of an induction-coil, and an interrup-"cror circuit-closer comprising contacts 14 and 15, the former being adiustable. The contact 15 isfixed upon a yie ding strip orextension. 16, fixed upon the unmounted end of the armature 5 and having its other end adjustab ly secured, preferably by being caught in a slot 17, formed in a support 18, the latter.

being adjustable transversely of the springstrip 16 by means of a screw '19 and slot 20. It will be seen that the strip vibrates with the armature, so that the interrupters or automatic circuit-closers operate alternately form shown the circuit 11 is closed by the movement which breaks the circuit 2. The secondary 21 of said induction-coil. is connected in the line 22 which also includes at each station a call device 23, which may beeit-her in the form of a bell-buzzer, telephone receiver, or other suitable form. The line may be grounded at 24 or a metallic circuit may be used.

It will be understood that when the pushbutton or circuit-closer is operated the armature and interrupter in the circuit 2 vibrate rapidly, and through the interrupter or circult-closer 14 15 the circuit 1 1 is rapidlymade and broken, whereby alternating electrical impulses are produced in the secondary 21 and in the line 22, said impulses effecting the call 23 at the other end of the line, as hereinafter explained, and without interfering with the ordlnary telegraphic instruments in use on the same line, as the currents transmitted over theline are of great frequency and of high potential. The rapid impulses are transmitted automatically over the line so long as the circuit 2 remains closed by the si naling or calling key orpush-button, W ereby long and short signals maybe'transmitted' to designate the office called or single or numerical calls of uniform lengthcan be given. My invention also includes use of a signaling or calling key in the local circuit 11 or in the line-circuit22 in lieu of the circuit closcr in circuit 2.

At Fig. 2 it will be seen that two imiuctioncoils are used, the secondaries 25 and 26 he 111g connected in parallel 111 the line, and the primaries l7 and 28 being commclcd in parallel in the circuit 11..

In the form shown at Fig. 3 the secondaries, (designated as 29 and 30,) are also conneoted. in parallel in the line: but the prime 't. e.,' one closing as the other breaks. In the breaks the sounder-circuit ries 31 and 32 are included in. independent local circuits 33 and 34, each having interrupters and each interrupter having one member or contact upon the spring 16, so that both independent circuits are made and broken simultaneously by the movements of the armature 5, the movements of the latter being controlled, of course, by the signaling or calling ke 1 before described. The strength of t e line-current "is thereby increased in proportionto the number of coils i-ndtlie current energy employed in the local circuit or circuits.

indicated diagrammaticallyin Fig. I, 35 being the key, 36 the switch, 37 the relay-magnet, which may bccut out of the line by a switch 38, 39 being the local sounder-circuit, including the sounder 40 and battery 41, and 42 the relay-armature, which makes and a paratus thus indicated at 1i e telegraphic apparatus for duplex or uadruplex Working is practically cut out of the telephone calling-circuit b means of'a shunt-circuit '43 around suc 1 apparatus, which shunt-circuit includes a suitable con- 'denser 44. A two-way switch 45 is preferabl'y provided, one contact-point of the switch 45 being normally closed to receive a call, the circuit then being from the line 22 through condenser 44, switch 45 to the callreceiver 23; t 161360 to earth, as at 24, has cutting out the resistance of coil 21 when receivin a call. To vscnda call, the switch 45 is c anged to the other-contactpoint, the circuit then being from line 22, through condenser 44, switch 45, to bindingpost 47, to coil 21, call-receiving apparatus 114, and thence to earth 24, as before. By this arrangement of circuits :1 call can be sent or received at all times even through the circuit containingthc telegraph-key and other apparatus be open; but if the same is closed and offering two circuits to the currents fl'rom the line 22*, since the condenser offers but a small resistance to the telephone-currents and the telephone-call currents as com- ,pared to that offered by the telegraph apparatus and as the telephone-call currents are of great frequency and high potential, only a small percentage passes through the telegraphic apparatus, which therefore is not affected.

Fig, 1 or other Variations may be resorted to within the scope of my invention-as, for instance, in lieu of the call-receiver 23 in the main line, shown as a telephone-receiver, a sensitive A polarized or telephone relay may be used,

controlling a local circuit in which a bell or other suitable call-receiwng apparatus may i Y be included and operated by a local-battery current, as and in-thc H ISJlIlQIYWGll known in connection with telegraph-relays and the sounderin a local circuit.

The usual telegraphic instruments are also The telegraphic Having thus described my invention, I claim- 1. In a telephonic calling. apparatus, two independent local circuits/an automatic resilient vibrator arranged to make and break saidlocal circuits alternately, an electromagnet connected in one of said local circuits attracting said vibrator in one direction, an induction-coil having the primary thereof connected in the local circuit unconnected with the electromagnet and having the secondary thereof connected in a line-circuit, and a suitable receiver connected in the line-circuit and arranged to control a local circuit at the receiving end, said local circuit including a suitable call-receiving apparatus;

2. independent local circuits, one of said cir silient vibrator arranged to alternately make and break said local circuits, said vibrator comprising a pivoted. armature adapted to be attracted by said electromagnet when its circuit is closed, and a resilient extension 1n such manner as of contact with the magnet.

3. In a telephonic calling ap aratus, two independent local circuits, an e ectromagnet connected inone of said circuits, an induction-coil having the primary-thereof connccted in the other local circuit and having the secondary thereof connected circuit, and a resilient vibrator arranged to make and break said local circuits alternately, said vibrator comprising a pivoted armature dis osed adjacent to said electromagnct and lihving a spring extending from the free end thereof, said spring hav'mg'its other end adjustably secured so as to hold the armature normally out of contact with said electromagnet.

4. In a telephonic calling apparatus, two independent local circuits, -oneof said circuits including an electromagnet and a resilient vibrator arranged to alternately make and break said local circuits, said vibrator comprising an and adapted to be attracted by said electromagnet when its circuit is closed, and aresilicnt extension at the free end of said armaturc, said resilient extension being adjustl ably secured at the end remote from the armature in such manner as to hold the arma turc normally out of contact with the said clectromagnct. r

5. in a telephonic calling apparatus, two I independent local circuits, one of said local circuits including an clectroniagnet, a resilient v -ibrator actuated by said electromagnet to make and break said local circuit: altcrnatcly, and an induction-coil having its primary connected in the local circuit not l including the elcctromagnct and having its l secondary connected to line.

In a telephonic calling apparatus, two

cuits including an'electromagnet and a, re-' from said armature having the end secured.

to hold the armature out in the line- ICO armature pivoted at one end mien 5mm MM w its mil fixami 1; 5013 making the g tn: pzimazy silein ,-..,"aw, t im 752m 10ml am me sized 

